1. Field of the Invention
The present invention relates to a curable composition for encapsulating an optical semiconductor and an optical semiconductor apparatus using the same.
2. Description of the Related Art
It has heretofore been proposed, as a curable composition, a cured product which is well-balanced in the properties of heat resistance, chemical resistance, solvent resistance, mold releasability, water repellency, oil repellency and low temperature characteristics can be obtained from a composition comprising a linear fluoropolyether compound having at least two alkenyl groups in the molecule and a perfluoropolyether structure in the main chain, a fluorine-containing organo hydrogen siloxane having two or more hydrogen atoms directly bonded to a silicon atom in the molecule and a platinum group compound (Patent Document 1).
Moreover, it has been also proposed a composition to which self-adhesiveness is provided to a metal or plastic substrate by adding an organopolysiloxane having a hydrosilyl group and an epoxy group and/or a trialkoxysilyl group to the composition (Patent Document 2).
Furthermore, it has been proposed a composition in which adhesiveness to various substrates, particularly to a polyphenylene sulfide resin (PPS) or a polyamide resin is improved by adding a carboxylic acid anhydride to the above-mentioned composition (Patent Document 3). In addition, in Patent Document 4, it has been proposed a composition which can prevent from lowering in brightness even in the presence of a corrosive acidic gas or an alkaline gas.
However, among the cured products obtained by curing the actually prepared compositions of the prior art, when the material having a Type A durometer hardness regulated by JIS K6253-3 of as low as 20 or so is used as an encapsulating agent of a light emitting diode (in the following, it is referred to as “LED” otherwise specifically mentioned), there were cases where impact resistance as an encapsulating agent was insufficient. For example, when the optical semiconductor apparatuses in which the LED is encapsulated by the cured product in bulk are to be arranged to a certain direction and a posture by using a bowl type vibration parts feeder, the problem frequently occurred that a bonding wire connecting the LED chip and the electrode had been disconnected by the impact due to collision of the optical semiconductor apparatuses to each other.
On the other hand, when the hardness of the cured product is heightened to improve the impact resistance, the problem was generated that the adhesiveness of the cured product to the package material of the LED, particularly to a polyphthalamide (PPA) which is a representative material thereof was insufficient.